overdrive/fuzz quest part 2

with over 50 pages in part one, I figured that it's probably time to start part two.

since the last thread, i've built a few new ones, including the Black Cat OD-1, the D*A*M red Rooster, the Smallsoundbigsound Sparkle Motion, Death by Audio Fuzz War (V1), Paul Nelson's Citrus Graphic (only I omitted the FAC on it since I like it better without it), the Baldwin-Burns Buzzaround (exact clone) and mictester's 'Buzzaround-Alike'.

on all of them, I first built them completely stock and then slightly modded them to make them more to my liking.

to start part 2, i'm posting the only one that's mounted in an enclosure (I should have a few others mounted in a few days). the Black Cat OD-1 (a.k.a. the Freddie Fuzz)

i built it following the schematic exactly, but to be honest, I really didn't care for it at all. it was kinda muddy and the distortion had a fizzy decay on all of the notes. here's what the manufacturer says about it:

" The Black Cat OD-1 is an original design Fred created based on the unique properties of the OP275, a dual operational amplifier chip made by Analog Devices. The OP275 is a high-quality op-amp that gives a distinctive linear output waveform. The Black Cat OD-1 can go from clean, to slightly crunchy, to all-out saturated distortion. It is unique in that it is extremely sensitive to the guitar; it responds to the player's pick attack, and like a good Fuzz Face, it cleans up well when you roll back the volume on the guitar. The Black Cat OD-1 has been used by Scott Henderson, Steve Lukather, Beck, Lyle Workman, Kyle Cook (Matchbox Twenty), and many others."

that sounded pretty impressive to me, and the youtube clips of it sounded pretty darn good, so that's why I built it, but unfortunately, for me, it was a mediocre sounding pedal at best, and I wasn't even going to mount it in an enclosure to complete it.

i've found that this circuit has actually been around quite a while, and some of the schematics used an LM1458 in it so decided to try 20 other dual opamps in it to see if I could solve the fizzy decay issue. some did it less and others did it more. I also first tried running it on 18 volts but that didn't help (it actually made it a little worse).

well, after all of that (a couple of hours), the OPA2604 was the only one that did the trick, and got rid of all of the fizz. now, to give it a little more top end but keep it smooth, I replaced the three small picofarad filter caps with lower values and used silver mica ones. finally, i removed the 430 ohm power limiting resistor and replaced it with a jumper so the pedal got the full 9 volts. after those mods it sounds great, still retains all of the character of the original design, but got rid of everything that I didn't like about it.

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IMO, the Sparkle Motion is a super simple circuit and IMO, it's okay stock (and i built mine to the exact stock specs), but I find the circuit to be a little dark & muddy, which is usually the case for a single germanium transistor booster. i didn't find a use for the bright setting so i'll end up omitting the switch for it in mine. it's basically a booster with a little bit of 'hair' when you adjust the bias. SS/BS recommends an NPN ge tranny with an hfe of about 100 and that's what I used. I also tried ones with higher and lower hfe's but the one that measured 98 sounded the best to me. I also tried using a few different silicon transistors in it and I actually like them better. they're not as dull sounding and can provide a little more dirt without being too fizzy about it. I ended up using a 2N5089 (with a lot higher gain than the ge) and then modded the bias control and I really like the pedal now.

John, with all your knowledge and experience with dirt pedals, haven't you ever felt like designing your own stuff and beginning an online shop? Kinda like what Fuzzrocious is doing? I'm pretty sure would buy your pedals without hesitation.

John, with all your knowledge and experience with dirt pedals, haven't you ever felt like designing your own stuff and beginning an online shop? Kinda like what Fuzzrocious is doing? I'm pretty sure would buy your pedals without hesitation.

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i've built and sold a few special requests, and have built a few for friends, but i really don't have the time to make very many of them for sale. I've also designed a couple of my own, but generally like to make clones of my favorite circuits and then, if necessary, mod them more to my liking. after making about 110 different ones, i've found that most boutique pedals are pretty much existing designs with a couple of tweaks here and there.

Which is sad and which is why more people should consider the DIY route.

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hmmmm. i guess that i don't find it to be sad since it seems that almost every individual player is looking for something a little different in each pedal(& we all have different tastes). sometimes you'll hear someone say that they love a particular pedal but wish it had a little more of this, or a little less of that.

i built a couple more yesterday and finished testing them. i'm just waiting for their enclosures to arrive. one of them is the 1978 opamp big muff (a super heavy fuzz/distortion) with an added clean blend. it's quite a bit different sounding than the standard four tranny muffs. the other one is the Crowther Hotcake XLF. the hotcake can go from a clean boost to a slight overdrive, to a very heavy distortion.

I have a weird question: I've owned both the old and new Crowther P&C pedals at one time or another and, to my ears, the old single switch sounds better. I'm wondering if adding that second switch somehow adds resistance in the circuit or if the whole thing is my imagination and I need to get a life somehow?

I didn't know about the two different versions but IMO, the extra switch wouldn't make any difference. it makes me think that there were possibly other slight changes to the circuit between the two. the only one that I have the schematic for is the later one.

as far as the hotcake goes, i first built it compleltely stock (only with the vintage version's LM741 chip, but with the modern version's presence control) and it was okay, but it lost a little low end and was a bit too fizzy up top. after modding the clipping filter to what I believe is the XLF version, it's an awesome sounding overdrive and sounds like no other pedal that i have.

I added a master volume to it since the stock 'balance' control actually changes the tone and drive since it loads the output of the circuit (when you turn the balance down, it actually gets grittier). that way I can get even more sounds out of it.

the chip that you see in the internal pic below is just a charge pump to reverse the polarity from +9 volts to -9V since it uses three NOS Ge transistors. that way I can run it with a standard 9V boss adapter.

hmmmm. i guess that i don't find it to be sad since it seems that almost every individual player is looking for something a little different in each pedal(& we all have different tastes). sometimes you'll hear someone say that they love a particular pedal but wish it had a little more of this, or a little less of that.

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Don't misunderstand me. The only thing I find sad is that most "boutique" pedals are simply overpriced clones with a few tweaks. You said it yourself.